A massive earthquake struck Japan on Friday. The quake registered 8.9 on the Richter scale. It was the most powerful tremblor to hit Japan since officials there began keeping records 140 years ago. Before this, the country's worst earthquake was an 8.3 tremblor in 1923. Japan lies on the "Ring of Fire"—an area rimming the Pacific Ocean. About 90 percent of the world's earthquakes take place in that region. Friday's quake ranks as the fifth largest quake in the world since 1900, scientists say.

Dozens of cities and villages along a 1,300-mile stretch of coastline were shaken by violent tremors. Because it struck below the Pacific Ocean, the quake set off waves as high as a three-story building. The monstrous waves, called a tsunami (soo-nah-mee), swept away homes, boats and cars as the water roared several miles inland, stopped, and rolled back out to sea. Highways buckled, telephone lines snapped, and fires broke out. Aftershocks, or smaller quakes, followed the big quake, causing more damage and forcing residents to seek safety outside.

Tokyo, Japan's capital, is about 230 miles away from the center of the quake (Click here to see a map of Japan). But even there, people felt the ground shake. Buildings swayed, at least 2 million homes were without electricity, and trains stopped running. "At first it didn't feel unusual, but then it went on and on. So I got myself and my wife under the table," said Jesse Johnson, an American living in Tokyo. "I've lived in Japan for 10 years and I've never felt anything like this before. The aftershocks keep coming. It's gotten to the point where I don't know whether it's me shaking or an earthquake."

Waves at Jet Speed
The effects of the underwater quake are being felt far from Japan. The tsunami raced thousands of miles across the Pacific Ocean. The waves can be hundreds of miles long and travel at 500 miles per hour —the speed of a jetliner. Officials issued warnings to nations including Japan, Russia, Indonesia, New Zealand and the West Coast of the United States.